I have accidentally deleted a folder containing several VMware virtual disk files (.vmdk) that are over 4gb size. I haven't done any changes on the disk after I deleted these files maybe I deleted a file or two after that but I didn't write any data on the drive. Files are deleted from a ntfs partition that is located on a raid 0 array (2x1TB) if that helps with anything. Operating System is windows 7 x64 and files are deleted by hitting shift+delete. With Rstudio I can see one 3.98GB .vmdk file but all other .vmdk files I want back are over 4GB and RStudio shows 0 byte as file size for these files.

Alas, when Windows deletes large files, it may delete a lot information about them, including their so-called run-lists, which makes file recovery very hard.
There are two options left in your case: disk scan for known file types: disk scan, or a manual inspection by a data recovery professional.
If you choose disk scan, you need to create a file description for vmdk files. The article Creating a Custom Known File Type for R-Studio may help you.